1. Field of the Invention
The present invention relates to a printing apparatus and more specifically to a printing apparatus, a printing method and a program which perform printing by assigning print data for two or more pages to one sheet of paper in a marginless printing system.
2. Description of the Related Art
With a price reduction and performance improvement of so-called digital cameras in recent years, a system for printing image data shot by a digital camera with a printer has come into use in addition to an existing system by which a photograph is shot and printed using a conventional silver salt picture film.
FIG. 5 shows a printing system in which a host computer and a printing apparatus are interconnected through an interface. In the printing system of FIG. 5 consisting of a host computer 1002 and a printer 1003, a variety of data editing is performed by various application programs running on the host computer 1002. Then the edited data is output as print data through an interface 1001 (e.g., Ethernet®), USB and IEEE1394) to the printer 1003 for printing. In this printing system, when print data is to be printed by the printer 1003, the associated application program causes a printer driver operational on the host computer 1002 to display a dialog box for a user to specify print parameters such as paper size used for printing before the application outputs the print data.
In a printing system in which a digital camera is used in place of the host computer, shot image data is output as print data from the digital camera through the interface to the printer for printing. Further, in a printing system in which a storage media is connected to the printer, image data stored in the storage media is output as print data to the printer for printing. In these printing systems, an operation unit of the digital camera or of the printer allows the user to specify the print parameters such as paper size.
There is a general trend for silver salt pictures being printed with no blank margins and, in line with this tendency, printers have entered the market which allow for a printing without leaving blank margins (referred to simply as a marginless printing) to produce photograph-like prints. Many of these printers, as shown in FIG. 1, realize the marginless printing by outputting a print image 501 of a Wi×Hi size, slightly larger than an effective print area of a print medium, Wc×Hc, to produce a printed image slightly overrunning the edges of the effective area of the print medium. In some printers, the image output for those portions outside the effective area is printed to exactly the edges of the print medium and, in others, the overrunning printed portions are cut away (Japanese Patent Application Laid-Open No. 2002-187261).
Meanwhile, there are printers and printing systems available which, to reduce the number of printed sheets or to provide an overall view of a document, compresses a plurality of pages of print data and allocate them to one sheet of paper for printing (multipage printing function). For example, a plurality of pages of print images, like the ones 501 of Wi×Hi size shown in FIG. 1, are assigned to divided areas 801-804 of a single sheet 810 and printed, as shown in FIG. 3. While in FIG. 3, all the printed images shown are the same, actual printed images assigned to one page may be different (Japanese Patent Application Laid-Open No. 11-147345 (1999)).
When a multipage printing, such as shown in FIG. 3, is performed in a marginless printing mode of FIG. 1, a combination of multiple print images is generated as print data of a size slightly larger than and overrunning the effective area of the print medium 610, as shown in FIG. 2. That is, an output image 601 is generated which comprises a plurality of print data arranged to contact with each other at their sides, and this output image is printed. Individual printed images 901-904 in FIG. 4 are each deviated from their own print areas. Particularly when the same images are to be printed, a problem arises that the way the individual images are deviated varies from one print area to another.